Positioning apparatus



Feb. 28, 1967 J. A. CUPLER ll POSITIONING APPARATUS 2 Sheets-Sheet 1 FIG. 2

Filed May 12, 1964 FIG. I

IIHHIIIIII AMPLIFIER Enos INVENTOR JOHN A. CUPLER, II

FIG.4

ATTORNEY Feb. 28, 1967 J CUPLER 1 3,305,930

POSITIONING APPARATUS Filed May 12, 1964 2 Sheets-Sheet 2 INVENTOR JOHN A. CUPLER, 11

ATTORNEY United States Patent Ofifice 3,305,930 Patented Feb. 28,1967

3,305,930 POSITIGNHNG APPARATUS John A. Cnpler II, Copier Drive, La Vale, Md. 215il2 Filed May 12, 15564, Ser. No. 366,714 20 Claims. (Cl. 33147) apparatus emimachine tools,

This invention relates to positioning nently suited for many uses including gages and manipulators of various types.

Inasmuch as positioning apparatus of known types is almost invariably subject to some degree of lost motion or backlash, as greater precision operations become feasible, the greater will be the error ratios encountered. Such backlash has been inherent, in varying degrees, in positioning apparatus of all types including those relying upon mechanical movements, hydraulics, pneumatics, or otherwise. Moreover, the adverse effects of backlash have been increased in known positioning apparatus as a function of the forces encountered in the use of such devices.

In accordance with the present invention, it is sought to overcome the deficiencies of hitherto conventional apparatus by making it possible to produce positioning movements, accurately and in small increments over a desired range of movements, without the introduction of the errors ordinarily experienced by the presence of lost motion or backlash.

It is among the objects of the present invention to provide positioning apparatus comprising support means, first and second resilient members having intersecting longitudinal axes, each having an end fixed to the support means and each having a free end, spacing means interposed between proximate portions of the members and applying stress to the members within their elastic limits under all conditions of operation, and adjustable force applying means engaging the first member to impart movement thereto transversely of its axis and to produce transverse positioning motion of the second member through the spacing means. The spacing means preferably provides a point contact intermediate the members and may include a roller having an axis substantially parallel to the axis of the second member, a roller having an axis substantially perpendicular to the axis of the second member, a spherical member, and/ or a pair of interengaging rollers having substantially perpendicular axes. The force applying means may be actuated manually and/or may assume the form of a motor and may be provided with calibrations.

A plate may be secured to a free portion of the second member so as to overhang the support means and a leg spaced from the second member may be secured to the plate so as to bear on the support means, and the legs may be secured to the support means. One or both of the members may be provided with locally reduced crosssections and one or both of the members may be integral with the support means. The members may be unitary and they may be composed of a material having a low coefficient of expansion.

Positioning apparatus according to the present invention may comprise support means, first and second resilient members having substantially perpendicular longitudinal axes, each member having an end fixed to the support means and each having a free end, an element to be positioned interconnected with the second member, rigid spacing means interposed between the members maintaining their free ends in spaced relationship and applying bending stresses in the members under all conditions of operation, and adjustable force applying means engaging the first member for imparting transverse move ment thereto, the spacing means transmitting components of movement from the first member to the second member to impart positioning movements to the element.

A machine tool embodying the present invention for relatively positioning a tool element and a work element may comprise support means, first and second resilient members having intersecting longitudinal axes, each member having an end fixed to the support means and each having a free end, the second member carrying one of the elements, the other of said elements being mounted on the support means, spacing means interposed between proximate portions of the members applying bending stresses in the members within their elastic limits under all conditions of operation, and adjustable force applying means engaging the first member to impart movement thereto transversely of its axis and produce. relative motion between the elements through the spacing means and second member. The second member of such a machine tool may carry the tool element, or it may carry the work element if preferred.

The present invention also contemplates gaging apparatus comprising support means, first and second resilient members having intersecting longitudinal axes, each having an end fixed to the support and each having a free end, spacing means interposed between proximate portions of the members and applying bending stresses in the members within their elastic limits under all conditions of operation, motion sensing means connected to one of the members, adjustable force applying means engaging the first member to impart movement thereto transversely of its axis and produce transverse positioning motion of the second member through the spacing means, and calibrated means connected to the sensing means to produce an indication. Such gaging apparatus may include sensing means controlling an electrical circuit including an amplifier whose output circuit includes the calibrated means. i

A more complete understanding of the invention will follow from a detailed description of the accompanying drawings wherein:

FIG. 1 is a side elevation of positioning apparatus embodying the present invention;

FIG. 2 is a side elevation of another form of positioning apparatus embodying the invention;

FIG. 3 is a plan View of another embodiment of the invention;

FIG. 4 is a side elevation of the embodiment depicted in FIG. 3;

FIG. 5 is an end elevation of the embodiment depicted in FIGS. 3 and 4;

FIG. 6 is a fragmentary view, partially in section and on an enlarged scale depicting a detail of the construction shown in FIG. 4;

FIG. 7 is a side elevation depicting another embodiment of the positioning apparatus contemplated by the present invention; and

FIG. 8 is a front elevation, partially broken away, of the embodiment depicted in FIG. 7.

Referring first to the form of the invention depicted in FIG. 1, a first resilient member 10 having a longitudinal axis 12 extends substantially horizontally from vertical support means 14 towards a second resilient member 16 having a longitudinal axis 18 extending substantially vertically from support means 20. The members 10 and 16 are maintained in bending stress, within their elastic limits, at all times by means of one or more balls or rollers 22 interposed between proximate surfaces of the members. Such interposition is effected by producing a separation between the proximate surfaces of the members by deflecting one or both ofthem until the gap between them is suflicient to permit the introduction of suitable spacing means in the form of one or more such balls or rollers 22. The initial positions of the members 10 and 16 have been depicted in broken lines on a somewhat exaggerated scale, so that it will be apparent that these members in the full line positions shown are always under bending stresses for all conditions of operation. After this relationship has been established, an adjustable force applying means, illustrated by a screw jack 24 in FIG. 1 will be introduced between the first resilient member and the support means in order to produce any desired degree of fur- .ther deflection of the member 10. The head 26 of the jack 24 can be elevated and lowered by inserting a rod or handle 28 in any of aplurality of openings 36 extending radially into an annulus 32 carried by the lower end of the screw 34. Actuation of the handle 28 to elevate the head 26 of the jack will elevate the free end 36 of the member 10 causing the one or more balls or rollers 22 to transmit the movements produced. The members 10 and 16 behave like cantilever beams under bending stresses so that movements of points thereon, in the form of the invention depicted in FIG. 1 will be arcuate. Accordingly, the element 38 to be positioned will partake of arcuate motion, so that either its horizontal or vertical component or both can be utilized for imparting motion to another body if desired. The end 36 of the member 10 may be formed with a suitable socket or depression 40 for the reception of each ball or roller 22 employed which will then produce a point or line contact with the proximate surface portion of the member 16 depending on whether a ball or a roller is employed.

It will be understood that the support means 14 and 20 can be unitary, and they will preferably assume such a form in practice whether they are formed integrally or welded together or bolted together, Moreover, the ends of the members 10 and 16 adjacent the support means will be securely fastened thereto in a suitable fashion as by welding or through the use of bolts. It will be under stood that the adjustable force applying means 24 plays no part in the production of the initial stresses in the members 10 and 16, whose separation can be effected by any means available, such as a suitable jack, in order to permit the insertion of the one or more balls or rollers 22. Thereafter, the device employed to produce the initial separation of the members for this purpose will be removed and the adjustable force applying means positioned to produce the positioning movements. In view of the relative stiffness of the resilient member 10, the threads 34 of the screw jack 24 will always bear against their complementary threads in the same direction while the head 26 is opposing the stress maintained in the member 10.

The members 10 and 16 may be composed of a variety of materials such as various steel alloys and where it is desired to counter the effects of temperature changes to a maximum degree, materials such as Invar or other materials having low coeflicients of expansion can be employed.

In the modification of the invention depicted in FIG. 2 there is a base or supporting means 42 having an upwardly extending column 44 from which the first member 10 extends substantially horizontally towards a plate 46 partially overhanging the base and supported in part by the second member 16 in conjunction with a supplemental leg 48 spaced from the second member 16, secured to the plate 46 and bearing on the support means 42. Interposed between the proximate ends of the first member 10 and the plate 40 are depicted a roller 50 bearing upon the first member 10 and upon a ball or roller 52 seated in the proximate end of the plate 46. Either or both of the elements 50 and 52 will be inserted between the member 10 and the plate 46 while these members are suitably forced apart to a degree sufficient to permit insertion of one or both of these elements to constitute spacing means. The leg 48 having its lower end fixed to the base 42 defines with the member 16, the base 42 and the plate 46 a parallelogram so that movements imparted to the plate 46 by bending of the member 10 will tend to maintain the upper surface of the plate 46 parallel to a given plane at all times. Accordingly, a tool 54 diagrammatically shown as carried by the plate 46 will similarly receive movements so that the tool will also remain parallel to a given plane. A workpiece 56 has been diagrammatically shown as supported between work holders 5?; and 66 containing V-slots 62 to permit rotation of the workpiece.

After the members 10 and 16 have been subjected to the required bending stresses by interposition of one or more of the elements 50 and 52, a suitable adjustable force applying means 64, again assuming the form of a screw jack, will be interposed between the lower surface of the member 11) and the base 42 to produce deflections of the member 10 in desired increments. The jack can be actuated by means of a handle 28 as before and/or by means of a motor 66 which may be a thermal motor, a hydraulic motor, a pneumatic motor, an electric motor, a spring motor, or any other desired type of motor to produce the order of movements required for the application for which the positioning apparatus is intended. In order to read the extent of movements imparted manually or by a suitable motor, a pointer 68 carried by the jack 64 can be employed in conjunction with a suitably calibrated scale 70, suitably supported in a manner not shown. A ball 72 can be interposed between the upper end of the jack 64 and the lower surface of the member 10 and received in suitable seats for the transmission of movement between the jack and the member 10. The member 10 is provided with a reduced portion 74 in order to impart desired bending characteristics to the member. Similarly, the member 16 is shown as containing a reduced portion 76 and the leg 48 contains a reduced portion 78. In order to measure the output movements imparted to the second member 16, a strain gage 80 can be secured to an appropriate portion of the member 16, so that a meter 82 electrically connected in circuit with an amplifier 84 and the strain gage 80 will give direct readings of movements produced for precision adjustment of the tool 54 relative to the work piece 56. As will be clear to those skilled in the art, the strain gage 80 is merely illustrative of any of a number of types of sensing elements which can be attached to or positioned in the path of any portion of the system to produce the type of reading desired. Any two or more of the parts 10, 44, 42, 16, 48 and 46 can be made integral by welding or the like, if desired, or the integral association may be achieved by casting, extrusion, or otherwise.

With reference to the embodiment of the invention depicted in FIGS. 3, 4, 5 and 6, there is provided a base 42 in the form of a relatively heavy metal plate to which is secured the lower end of a relatively heavy and rigid column or post 44, from whose upper end there extends in cantilever fashion a first member 10 having a reduced portion 74, maintained in bending stress, within its elastic limits, under all conditions of operation by means of a pair of spaced rollers 50 bearing against the free end 86 of the member 10 and against the peripheries respectively, of a pair of rollers 52 mounted on pivots 88 carried by the plate 44 carried by the upper end of the second member 16 whose lower end 90 is secured to the base 42 and which contains a reduced portion 76 for determining the deflection characteristics. Here again the members 10 and 16 will both be stressed in bending when the rollers 50 are interposed between the member 10 and the rollers 52. Inasmuch as the axes of the rollers 50 and 52 are arranged at right angles, point contacts will be produced between them, in the interests of precision and accuracy of movements transmitted. The plate 46 is additionally supported by means of the leg 48 carrying rollers 92 on pins 94 so as to enable the plate 46 to carry an element 96 to be positioned of substantial mass without introducing substantial deformation of any of the parts by virtue of the mass supported. The element to be positioned can be a work holder or a tool holder for such tools as grinding wheels, milling cutters or any other type of tool desired.

Input movements are applied to the member by means of a micrometer 98 containing conical recesses 108 in its opposite ends for the reception of balls 102, the lower ball being received in a conical recess 104 formed in a pad 106 carried by the base 42 and the upper ball being received in a conical recess 108 formed in a pad 110 bearing against the lower surface of the member 10. The micrometer 98 has one of its portions maintained fixed against rotation by means of a clamp 112 gripping a knurled portion 114, the clamp being suspended by means of a leaf spring 116 mounted on a support bracket 118 secured to the base 42 by means of machine screws 120. Thus, the clamp 112 will permit vertical movement of the non-rotatable portion of the micrometer but will restrain it against rotational movement. A lower knurled portion 122 carried by the rotatable part of the micrometer has secured thereto, in a suitable fashion not shown in detail, a handle 124, which for purposes of clarity has been depicted in FIG. 3 but omitted in FIGS. 4 and 5. The end of the handle 124 carries a pointer 126 which will move over a scale 128 as the handle is rotated to actuate the micrometer so as to give an indication of the position of the element 96 to be positioned or its displacement from a given position.

The form of the invention shown in FIGS. 3, 4, 5 and 6 is eminently suited for use in conjunction with a machine tool where the plate 46 will support either a tool element or a work element.

The form of the invention depicted in FIGS. 7 and 8 is eminently suited to serve as a gage. In this case, the base 42 has been depicted as a vertically extending member supported by a frame 130 with a post 44 having one end secured to the base and its other end secured to the resilient member 10 having its longitudinal axis in this instance extending substantially vertically. The second member 16 has its longitudinal axis, in this case, extending substantially horizontally from the base 42 and its free end is secured to the plate 46 between which and the member 10 a pair of rollers 132 and a pair of pads 134 are interposed so as to maintain the proximate ends of the plate 46 and the member 10 in spaced relationship and also maintain the members 10 and 16 under continued bending stress throughout their range of operations, within their elastic limits. The jack 64 is again interposed between the base 42 and the member 10 to impart movements to the member 10 by rotation of the jack by means of the handle 28 which is received in any one of the radial openings 30 provided in the disk 32.

The end of the jack and the opposed surface of the member 10 are provided with conical recesses 136 to receive a ball 138 through which motion is transmittedfrom the jack to the member 10.

A shaft 140 extending from the left of the disk 32 as viewed in FIG. 7 carries a dial 142 for rotation therewith relative to a pointer 144 secured to the base 42 by means of screws 146. As shown in FIG. 8, the dial 142 can be provided with a plurality of scales having diversely spaced divisions, adapting the apparatus for various ranges.

The lower end of the plate 46 is shown as having secured thereto a probe 148, which may be of a conventional type from which projects a contact 150 for engagement with a work piece 152 to be gaged, supported on an anvil 154 which is carried by the frame 130. The probe 148 is connected by suitable leads to an amplifier 156 which supplies an indicating instrument 158. The

leads from the probe 148 are shown as connected to an input of a double pole double throw switch 160 so that readings can be achieved with the same instrumentation from another point on the apparatus by means of a strain gage 162 secured to the member 16 and connected by means of suitable leads to another input of the switch 160. Accordingly, by manipulating the switch 160, readings can be made selectively from the probe 148 and the strain gage 162. The indicating instrument 158 may also be of a conventional type and is shown as having a knob 164 for scale selection. The scales available on such an instrument may well conform with the several scales provided on the dial 142 so that a prescribed deflection of the dial relative to the pointer 144 will produce a predetermined deflection on the indicating instrument 158.

In using the apparatus as a gage, a standard gage block can be mounted on the anvil 154 and the handle 28 manipulated until the contact element 150 of the probe 148 engages the standard. Then the dial 142 can be rotated relative to its shaft by loosening a set screw 166 to bring a prescribed division on the dial in register with the pointer 144. Similarly, if desired, the indicating instrument 158 can be adjusted so that its pointer corresponds with a desired division on the scale. Then the standard block can be removed and the work piece 152 introduced. In the event that the dimension of the work piece does not exactly correspond with that of the standard, there will be a deflection on the indicating instrument 158. The handle 28 will then be operated in the correct direction to bring the contact element of the probe 148 into contact with the work piece, whereupon a reading of the deviation of this dimension from that of the standard can be made on the dial 142, the indicatinginstrument 158, or both. The rollers 132 carried by the member 10 are supported on pins 88 in the same manner that the rollers 52 of FIGS. 3, 4 and 5 are supported on pins 88.

Within'the range of any instruments now available for determining the precision of the positioning apparatus herein'before described, no evidence of backlash or lost motion has been detected. Regardless of which direction of movement is imparted to the member 10 of the various embodiments described, positive movement of the member 10 is produced for each measurable increment of movement of the adjustable force applying means. Accordingly, the present invention adapts itself to myriad uses wherein precise positive movements are required.

In the embodiments of this invention illustrated in FIGS. 2 to 8, output motions can be obtained from the relatively heavy member 44 instead of or in addition to the motions produced by the second members 16 and their plates 46 or other elements associated therewith. Since the members 44 in the proportions shown, are relatively stiff, their movements are smaller than those of the members 16 at a given distance from the bases 42.

By employing arrangements of spacing means between the first and second members so as to be offset with respect to the central axes of these members, torsional components are also introduced into the first and second members, so that the element to be positioned will receive motion in a third dimension, a motion that is useful in conjunction with the tool feeds in machine tools for relieving the tool as it is retracted from a work piece, and in conjunction with gages as they are moved towards and away from a specimen undergoing measurement.

It is also contemplated that the spacing means, such as the rollers 50 of FIGS. 2 to 6, be tapered, contoured, or of other configuration that will impart predetermined output motions to an element to be positioned in response to progressive input movements or in accordance with any desired pattern. 7

The foregoing description will suggest to those skilled in the art many variations of the few specific examples set forth. Accordingly, the invention should not be restricted to those specific examples, but should be conoperation, and adjustable force applying means engaging said first member to impart movement thereto transversely of its axis and produce transverse positioning motion of said second member through said spacing means.

2. Positioning apparatus according to claim 1 wherein said spacing means provides a point contact intermediate said members.

3. Positioning apparatus according to claim 1 wherein said spacing means includes a roller having an axis sub stantially parallel to the axis of said second member.

4. Positioning apparatus according to claim 1 wherein said spacing means includes a roller having an axis sub-- stantially perpendicular to the axis of said second member.

5. Positioning apparatus according to claim 1 wherein said spacing means includes a pair of interengaging rollers having substantially prependicular axes.

6. Positioning apparatus according to claim 1 wherein said spacing means includes a spherical member.

7. Positioning apparatus according to claim 1 wherein said force applying means is manually actuated.

8. Positioning apparatus according to claim 1 wherein said force applying means is a motor.

9. Positioning apparatus according to claim 1 wherein said force applying means is calibrated.

10. Positioning apparatus according to claim 1 wherein a plate is secured to the proximate portion of said second member and overhangs said support means, and a leg spaced from said second member is secured to said plate and bears on said support means.

11. Positioning apparatus according to claim 10 wherein said leg is secured to said support means.

12. Positioning apparatus according to claim 1 wherein at least one of said members is provided with a locally reduced cross-section.

13. Positioning apparatus according to claim 1 wherein at least one of said members is integral with said support means.

14. Positioning apparatus according to claim 1 wherein said members are unitary.

15. Positioning apparatus according to claim 1 wherein said members are composed of a material having a low coefiicient of expansion.

16. Positioning apparatus comprising support means, first and second resilient members having substantially perpendicular longitudinal axes, each member having an end fixed to said support means and each having a free end, an element to be positioned interconnected with said second member, rigid spacing means interposed between said members maintaining their free ends in spaced relationship and applying bending stresses in said members under all conditions of operation, and adjustable force applying means engaging said first member for imparting transverse movement thereto, said spacing means transmitting components of movement from said first member to said second member to impart positioning movements to said element.

17. In combination with a machine tool for relatively positioning a tool element, positioning apparatus and a work element comprising support means, first and second resilient members having substantially perpendicular intersecting longitudinal axes, each member having an end fixed to said support means and each having a free end, said free ends providing relatively proximate portions said second member carrying one of said elements, the other of said elements being mounted on said support means, spacing means interposed between the proximate portions of said members, applying bending stresses in said members within their elastic limits under all conditions of operation, and adjustable force applying means engaging said first member to impart movement thereto transversely of its axis and produce relative motion between said elements through said spacing means and secand member.

18. In combination with a machine tool according to claim 17 wherein said second member carries said tool element.

19. Gaging apparatus comprising support means, first and second resilient members having substantially perpendicular intersecting longitudinal axes, each having an end fixed to said support and each having a free end, said free ends providing relatively proximate portions, spacing means interposed between the proximate portions of said members and applying bending stresses in said members within their elastic limits under all conditions of operation, motion sensing means connected to one of said members, adjustable force applying means engaging said first member to impart movement thereto transversely of its axis and produce transverse positioning motion of said second member through said spacing means, and calibrated means connected to said sensing means to produce an indication.

20. Gaging apparatus according to claim 19 wherein said sensing means controls an electrical circuit including an amplifier whose output circuit includes said calibrated means.

References Cited by the Examiner UNITED STATES PATENTS 2,128,314 8/1938 Nunn 74-89 X 2,540,961 2/1951 Osplack 33-179.52 2,954,701 10/1960 Berill 7489 X LEONARD FORMAN, Primary Examiner.

S. S. MATTHEWS, Assistant Examiner. 

1. POSITIONING APPARATUS COMPRISING SUPPORT MEANS, FIRST AND SECOND RESILIENT MEMBERS HAVING SUBSTANTIALLY PERPENDICULAR INTERSECTING LONGITUDINAL AXES, EACH HAVING AN END FIXED TO SAID SUPPORT MEANS AND EACH HAVING A FREE END, SAID FREE ENDS PROVIDING RELATIVELY PROXIMATE PORTIONS, SPACING MEANS INTERPOSED BETWEEN THE PROXIMATE PORTIONS OF SAID MEMBERS AND APPLYING STRESS TO SAID MEMBERS WITHIN THEIR ELASTIC LIMITS UNDER ALL CONDITIONS OF OPERATION, AND ADJUSTABLE FORCE APPLYING MEANS ENGAGING SAID FIRST MEMBER TO IMPART MOVEMENT THERETO TRANSVERSELY OF ITS AXIS AND PRODUCE TRANSVERSE POSITIONING MOTION OF SAID SECOND MEMBER THROUGH SAID SPACING MEANS. 